Causes

Doctors aren't sure what causes bladder exstrophy to develop. Researchers think that a combination of genetic and environmental factors likely plays a role.

What is known is that as the fetus grows, a structure called the cloaca (klo-A-kuh) — where reproductive, urinary and digestive openings all come together — doesn't develop properly in babies who develop bladder exstrophy. Defects in the cloaca can vary a lot depending on the age of the fetus when the developmental error occurs.